1. Field of the Invention
This invention relates to a hoisting device for a crane, more particularly to a hoisting device with a hanging unit which is rotatable and adjustable to a desired angular position.
2. Description of the Related Art
In the conventional way of transporting an article to a desired location with the use of a crane, cables on the crane are fastened to a hoisting device. The hoisting device has a hook hung therefrom, and the hook holds together the top ends of four hanging chains. The bottom ends of the hanging chains extend away from each other and are fastened to the corners of the article. In construction sites, it is frequent to hoist a modular form assembly into a building or from floor to floor with the use of a crane and then position the same at a location where concrete will be formed. When the form assembly is hung on the hoisting device, it would normally rotate. In order to place the form assembly in a proper position, the position of the form assembly must be manually controlled and adjusted by operators when the form assembly is unloaded from the hook of the hoisting device. However, because of its bulky volume and heavy weight, handling of the form assembly is difficult to be conducted by operators.